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Fluid Journal : Fluid Journal 1996-1998
1 Fluid Journal Winter 1996 Table 1. Effect of 2 x 2 banded starter on grain yield, 1993. Starter Location NP 2O5 K2O Ashton Gridley Pana Oblong lbs/A --------bu/A- ------- 0 0 0 122 *** 171 187 25 0 0 131 175 194 030 0 126 175 183 25 30 0 142 185 196 0 020 128 171 184 25 -20 136 175 193 03020 126 170 187 353020 138 178 196 ***Damaged by herbicide at V7 growth stage. Summary: When early-season soil test levels of P and K were adequate, 2 x 2 starter containing N + P increased yields by 14 bu/A at two northern locations, regardless of previous crop. The same combination of N + P increased yields by 9 bu/A at one of two southern locations in 1993. Banding N + P consistently increased V6 plant weights of late-planted corn at all locations. Plant growth and yield were more consistently increased when starter fertilizer was side-banded instead of seed-placed. However; yield benefits from some seed-placed fertilizer treatments were observed at the same locations showing responses to 2 x 2 placement. Better yield responses occurred when N was injected and 2 x 2 starter containing N + P was used. No-till corn acreage has steadily increased in Illinois. No-till corn producers there have three options for applying the majority of their N: 1) preplant inject, 2) surface apply urea-based compounds, and 3) inject N at sidedress. Problems unique to no-till are nutrient stratification, increased surface residue, and cool wet soils that may influence nutrient availability. Experiments described here, begun in 1993 at four locations, will show evaluations of corn response to: 1) 2 x 2 starter applications with factorial combinations of N, P, and K, and 2) seed-placed fertilizers with various N, P, and K rates. Experimental locations and soils were varied to gain a better understanding of how environment might influence those treatments. K.B. Ritchie, Dr. R.G. Hoeft, Dr. E.D. Nafziger, L.C. Gonzini, J.J. Warren Starters Perform More Consistently Than Seed-Placed Fertilizers Illinois researchers compare 2 x 2 starter with seed-placed fertilizer treatments in no-till corn field studies. Combinations pack punch In 1993, plant weight at V6 was consistently increased by 2 x 2 treatments of 25-0-0, 25-30-0, and 25- 30-20. At Ashton, a northern continuous corn location with soil testing high in P and K, starter with N + P (25-30-0 or 25-30-20) increased yields by 15 to 20 bu/A (Table 1). In Oblong, these starter combinations increased yields by 9 bu/A. The Oblong location yielded about 60 bu/A above the average for that soil type, so it is likely that N became yield limiting, and the N in the starter provided the extra boost. In 1994, plants at Oblong showed a strong response to starter K fertilizer because the soil K test was low and no additional K was broadcast. Plant weight and yields were similar to those in 1993 in that 25-30-0 performed similarly to 25-30-20 when soil K was adequate. Yields at both Gridley (corn after soybean) and Ashton (corn after corn) were increased by 14 bu/A with 25-30-0 or 25-30-20 starter (Table 2). Gridley and Ashton are in the northern half of the state and have heavier, colder, wetter soils, which should increase the likelihood of a benefit from starter. Seed-placed less consistent In 1993, seed-placed fertilizer rates of 10-10-0 and 10-10-10 in the NPK factorial portion of the experiment provided V6 plant weight and grain yield results similar to the 10-10-10 and 25-30-20 banded treatments (2 x 2). At Ashton, treatments receiving at least 10 lbs/A of N + K20 yielded better than check and performed similarly to the 2 x 2 banded starter. As with the 2 x 2 study, no yield differences were observed at Pana or Oblong, and Gridley was damaged by herbicide. There was no significant stand reduction by any of the seed-placed treatments, even at rates of 20 lbs N + K2O. In 1994, Ashton was cold and dry (Figure 1), which slowed germination and increased the amount of time the seed was in contact with the fertilizer.
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